Lamp base



FIG. 1 is a top plan view of a lamp base showing my new design;

FIG. 2 is a side elevational view thereof, the front, rear and oppositeside being identical;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a top plan view of a second embodiment of my new design;

FIG. 5 is a side elevational view thereof, the front, rear and oppositeside being identical;

FIG. 6 is a bottom plan view thereof.

The ornamental design for a lamp base, as shown and described.